Process for extracting oil from oil shale

ABSTRACT

Pyrolytic recovery of shale oil by passage of pulsed, laser beams through a body of crushed shale housed in an enclosure from which gaseous products are withdrawn by a vacuum pump. Operation of the vacuum pump is synchronized with the laser generators to generate negative pressure pulses between the energy pulsations of the laser beams.

United States Patent Yant [ 51 Mar. 28, 1972 [54] PROCESS FOR EXTRACTING OIL FROM OIL SHALE [72] Inventor: Millred R. Yant, Laredo, Tex.

[73] Assignees: Samuel S. Williams, Laredo; Samuel Herrmann; Cleo Hermann, El Paso, Tex. part interest to each [22] Filed: Apr. 18, 1969 [21] Appl. No.: 817,418

[52] (1.8. CI ..208/11,20l/l9, 201/35, 201/37, 202/134 [51] Int. Cl. ..Cl0g 1/02, C 10b 53/06 [58] Field olSearch ..208/1l;204/D1G. 11; 201/19, 201/35, 36, 37;202/134, 135; 203/100 [56] References Cited UNITED STATES PATENTS 3,449,;1s 6/1969 Knappetal ..2o1/19 3,227,642 1/1966 Lemelson ..204/ l 68 3,464,892 9/ 1969 Bennett ..208/ 1 1 OTHER PUBLICATIONS Gould, The Washington Post, May 31, 1966 Sharkey et al., Nature, Vol. 202, No. 4936, June 6, 1964, pages 988 & 989

Primary Examiner-Curtis R. Davis Attorney-Clarence A. O'Brien and Harvey B. Jacobson [57] ABSTRACT Pyrolytic recovery of shale oil by passage of pulsed, laser beams through a body of crushed shale housed in an enclosure from which gaseous products are withdrawn by a vacuum pump. Operation of the vacuum pump is synchronized with the laser generators to generate negative pressure pulses between the energy pulsations of the laser beams.

l 1 Claims, 4 Drawing Figures SHEET 1 OF 2 PATENTED MR 2 8 I972 INVIFNTOK.

PROCESS FOR EXTRACTING OIL FROM OIL SHALE This invention relates to the recovery of valuable hydrocarbons from hydrocarbonaceous solids such as oil shales and the like. More particularly, the present invention is concerned with an economic and efficient method and retort apparatus for recovering shale oil.

Various processes and apparatus have been devised for use in the pyrolysis of shale rocks in order to decompose the organic material and recover shale oil therefrom. Apparatus for accomplishing shale oil recovery has however been quite expensive in view of the material handling problems and the quantity of shale oil recovered for the amount of raw material that is retorted since too large a body of solid material could not be fully retorted in one operation. This problem is overcome, for example, in one type of known apparatusby carrying smaller quantities of the material to be retorted on vehicles passing through a retorting zone having liquid seals. Also, in this type of apparatus, the combustion supporting gas must be separately heated before injection into the retorting zone to react with the solid material. Although the use of laser beam radiation as a source of energy for rapid heating of coal has been investigated, the continued transmissivity of a large body of shale rock relative to a laser beam as combustion progresses does not persist andthe distribution of heat energy throughout the body of material of material presents a formidable problem that has not been heretofore overcome. Accordingly, an important object of the present invention is to provide a novel and improved method and means for recovering shale oil by use of the energy of laser beams to initiate and effectively maintain combustion within a relatively large body of crushed oil shale.

In accordance with the present invention, the bottom layers of a large body of oil shale are heated by pulsed laser beams. The heated shale when contacted by air drawn in to an enclosure, causes eduction of gaseous hydrocarbons that rise upwardly through the shale to a gas collection space. The rising gas and air heat the upper layers of the crushed shale in order to retort the entire body of shale. Liquid products gravitate downwardly to the bottom and are drawn off while the gas is drawn upwardly by vacuum pressure pulses synchronized to occur between the pulsations of the laser beams. Because of the synchronized vacuum pressure pulses, voids are intermittently produced in the body of crushed shale to maintain its transmissivity with respect to the laser beams which would otherwise decrease as the shale is retorted under the heat produced. The heat generated by the laser beams is also thereby distributed throughout to cause retorting of .all portions of the crushed shale body.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

FIG. I is a perspective view illustrating the apparatus of the present invention.

FIG. 2 is an enlarged transverse sectional view taken substantially through-a plane indicated by section line 2-2 in FIG. 1.

FIG. 3 is an enlarged partial sectional view taken substantially through a plane indicated by section line 3-3 in FIG. 1.

FIG. 4 is a simplified schematic sectional view of the apparatus.

Referring now to the drawings in detail, FIG. 1 illustrates the apparatus of the present invention generally referred to by reference numeral designed to carry out the oil shale recovery process. The apparatus includes a relatively large, elongated enclosure generally referred to by reference numeral 12 which has'abase or foundation 14 on which sidewall sections 16 are mounted to form wall assemblies on opposite longitudinal sides of the foundation. The sidewall sections are interconnected by a roof portion 18. The roof portion as well as the sidewall sections 16 are made of a suitable, opaque material such as steel plate. The sidewall assemblies formed by the sidewall sections 16 are interconnected at the opposite ends by radiation transmissive, end wall portions which are made of a material such as glass including an entry end wall portion 20 at one longitudinal end and an exit wall portion 22 at the opposite longitudinal end as shown in FIG. 3.

The enclosure 12 is filled up to a predetermined height with a large body of hydrocarbonaceous solids such as crushed oil shale 24 as more clearly seen in FIGS. 2 and 3 supported on top of the foundation 14 by a fire clay floor 26. A gas collection space 28 is formed above the body of crushed oil shale. As shown in FIG. 1, the roof portion 18 at the ends, are supported on opaque end wall sections 30 above the glass wall portions 20 and 22, said end wall sections having openings mounting hinged access doors 32 through which the oil shale is loaded into the enclosure.

Combustion supporting fluid such as air is supplied to the body of oil shale from any suitable source through an air intake conduit 34 which mounts a control valve 36 to regulate the quantity of air drawn in. Liquid hydrocarbon products or shale oils are withdrawn from the body of crushed solids 24 through a conduit 38 which extends upwardly through the floor 26 into the enclosure. A cutofi valve 40 is mounted in the conduit 38 in order to control the outflow of the liquid. A suction conduit 42 is interconnected with a plurality of exhaust pipes 44 that extend upwardly from the roof portion. Thus, gaseous products within the gas collection space 28 at various locations above the body of solids 24 are withdrawn from the enclosure through the conduit 42 to which a vacuum pump assembly 46 is connected.

As shown in FIGS. land 3, a pair of laser beam generators 48 are mounted externally of the enclosure 12 adjacent one longitudinal end. Thelaser beam generators are of the pulsed ruby type arranged to. direct a pair of pulsed laser beams 50 through the bottom layer of the body of solids 24. The beams thus enter the enclosure through one end wall portion 20 in horizontally spaced relation to each other, exiting from the other horizontally spaced end wall portion 22. The beams while passing through the body of solids generate the requisite amount ofheat for retorting purposes.

Referring now to FIG. 4, it will be observed that each of the laser'beams 50 is emitted from a conventional type of pulsed ruby laser generator 48. In order to obtain efficient and thorough retorting of the entire body of solids, the operation of the vacuum pump 46 is controlled by the synchronizing control 52 so as to time the negative pressure pulses applied to the gas collection space 28 between the pulsations of the laser beams '50 being pulsed at a predetermined rate. In this manner, the transmissivity of the body of solids 24 with respect to the laser beams are maintained as the gaseous products rise upwardly into the space 28 and the liquid products are drawn off through the conduit 38. The negative pressure pulses also draw in a regulated quantity of air through conduit 34 necessary to support the retorting process. Also, the gaseous products may be conducted through a condenser 54 as shown in FIG. 4 and then delivered by the vacuum pump 46 to a storage container 56.

By way of example only, the capacity of the retort enclosure 12 when the body of solids is filled to the top of the plate glass wall portions 20 and 22 will be 480 cubic feet leaving the gas collection space 28 which will be filled with gas from the pyrolytic action of the laser beams. The gas is drawn to the condenser 54 by a vacuum pump of 3 horsepower capacity with a 30 to 35 c.f.m. rating. The negative pressure pulses of the vacuum pump will be synchronized in continuous out-ofphase relation to the pulsations of the laser beams of 5 pulses per minute. A commercially available ruby laser generator of well-known construction and operation may be utilized. The glass end wall portions 20 and 22 will not only transmit the laser beams but will also permit visual inspection of the interior of the enclosure.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope ofthe invention.

What is claimed as new is as follows:

1. In a method of recovering hydrocarbons from a body of crushed, hydrocarbonaceous solids within an enclosure comprising the steps of: passing radiant energy having a predetermined rate of pulsations through the body of crushed solids; and withdrawing gaseous products from said enclosure by pressure pulses continuously out of phase with said pulsations of the radiant energy.

2. The method of claim 1 wherein said pressure pulses are negative in value to simultaneously draw into the body of crushed solids combustion supporting fluid.

3. The method of claim 2 including the step of conducting liquid products from the body of crushed solids.

4. The method of claim 3 wherein said solids are oil shale and said liquid products are shale oil.

5. The method of claim 1 wherein said solids are oil shale.

6. The method of claim 5 wherein said pressure pulses are negative in value to simultaneously draw into the body of crushed solids combustion supporting air.

7. In an apparatus for retorting a body of solids, an enclosure, means generating pulsating radiant energy passing through said enclosure for heating said solid material therewithin, and means connected to said enclosure for inducing flow of reaction gas through the solid material at a rate maintaining the transmissivity of the solid material with respect to the radiant energy.

8. The combination of claim 7, wherein said means for inducing flow of reaction gas includes a vacuum pump and control means connected to the pump for producing suction pulses synchronized in continuous out of phase relation to the pulsating radiant energy.

9. The combination of claim 8, wherein the radiant energy is a laser beam passed through a bottom layer of the body of solids.

10. The combination of claim 7, wherein the radiant energy is a laser beam passed through a bottom layer of the body of solids.

11. The method of claim 1, wherein the radiant energy is a laser beam passed through a bottom layer of the body of solids. 

2. The method of claim 1 wherein said pressure pulses are negative in value to simultaneously draw into the body of crushed solids combustion supporting fluid.
 3. The method of claim 2 including the step of conducting liquid products from the body of crushed solids.
 4. The method of claim 3 wherein said solids are oil shale and said liquid products are shale oil.
 5. The method of claim 1 wherein said solids are oil shale.
 6. The method of claim 5 wherein said pressure pulses are negative in value to simultaneously draw into the body of crushed solids combustion supporting air.
 7. In an apparatus for retorting a body of solids, an enclosure, means generating pulsating radiant energy passing through said enclosure for heating said solid material therewithin, and means connected to said enclosure for inducing flow of reaction gas through the solid material at a rate maintaining the transmissivity of the solid material with respect to the radiant energy.
 8. The combination of claim 7, wherein said means for inducing flow of reaction gas includes a vacuum pump and control means connected to the pump for producing suction pulses synchronized in continuous out of phase relation to the pulsating radiant energy.
 9. The combination of claim 8, wherein the radiant energy is a laser beam passed through a bottom layer of the body of solids.
 10. The combination of claim 7, wherein the radiant energy is a laser beam passed through a bottom layer of the body of solids.
 11. The method of claim 1, wherein the radiant energy is a laser beam passed through a bottom layer of the body of solids. 